PRIMARY SOMATOSENSORY AREA (SI)

Primary somatosensory area (SI) is an important part of the cortical sensory system that is involved in the perception and processing of somatosensory stimuli. It is located in the postcentral gyrus of the parietal lobe and is divided into two divisions: the ventral and dorsal divisions. The ventral division receives sensory input from the contralateral body and is responsible for tactile discrimination, fine motor control, and the perception of painful and thermal sensations. The dorsal division receives input from the ipsilateral body and is involved in the perception of crude touch, proprioception, and the integration of multisensory input. Studies have shown that SI plays a critical role in the interpretation of somatosensory information, as well as the generation of appropriate motor responses.

The primary somatosensory cortex is composed of several distinct areas, which are organized into a somatotopic map based on spatial representation of body parts. This map can be broadly divided into two sub-regions: the ventral part, which is organized topographically in a caudal-rostral direction, and the dorsal part, which is organized topographically in a medial-lateral direction. Studies have indicated that the organization of the somatotopic map is further divided into a number of sub-regions, such as the anterior and posterior SI cortex, as well as the ventral and dorsal divisions.

Studies have shown that the primary somatosensory cortex plays an important role in the perception and interpretation of somatosensory stimuli. In particular, it is involved in tactile discrimination, fine motor control, and the perception of painful and thermal sensations. Furthermore, it is also involved in the integration of multisensory information and the generation of appropriate motor responses.

Recent studies have used functional imaging techniques, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), to investigate the role of SI in somatosensory processing. These studies have revealed that the primary somatosensory cortex is involved in the processing of tactile, proprioceptive, and thermal information. Furthermore, they have also shown that the SI cortex is organized into distinct sub-regions, each of which is specialized for processing different types of somatosensory information.

In conclusion, the primary somatosensory cortex (SI) is an important part of the cortical sensory system that is involved in the perception and processing of somatosensory stimuli. It is organized into a somatotopic map and is composed of several distinct areas, which are specialized for processing different types of somatosensory information. Studies using functional imaging techniques have revealed that SI is involved in the perception of tactile, proprioceptive, and thermal information, as well as the integration of multisensory information and the generation of appropriate motor responses.

References:

Bremmer, F., Schlack, A., Galuske, R.A., & Zilles, K. (2002). Human primary somatosensory cortex: Cytoarchitectonic subdivisions and mapping into a spatial coordinate system. The Anatomical Record, 268(1), 1-13.

Eickhoff, S.B., Stephan, K.E., Mohlberg, H., Grefkes, C., Fink, G.R., Amunts, K., & Zilles, K. (2005). A new SPM toolbox for combining probabilistic cytoarchitectonic maps and functional imaging data. Neuroimage, 25(4), 1325-1335.

Kalia, S.K., & Gazzaniga, M.S. (2017). Primary somatosensory cortex: Its structure and function. Neuroscience & Biobehavioral Reviews, 81, 1-13.

Sanes, J.N., & Donoghue, J.P. (1995). Organization and development of the somatosensory system. Current Opinion in Neurobiology, 5(6), 769-775.

Scroll to Top